1. Technical Field of the Invention
The present invention relates to starters and, more particularly, to a starter having an electromagnetic switch, operative to open or close a main contact of a motor circuit, and a solenoid for pushing a pinion gear toward a ring gear of an engine.
2. Description of the Related Art
In the related art, there has been known an engine starter device of a structure disclosed in Utility Model Publication No. 56-42437 (Patent Publication 1). With such a structure, the engine starter device is comprised of an electromagnetic switch operative to open or close a main contact of a motor circuit, electromagnetic force means (an electromagnet device) having a function to push a pinion gear toward an engine via a lever, and a detector for detecting a meshing condition between the pinion and a ring gear. The electromagnetic force means acts to push the pinion gear toward the engine to be brought into meshing engagement with the ring gear. When this takes place, the detector device detects the presence of the meshing engagement between the pinion gear and the ring gear, thereby causing the electromagnetic switch to be actuated for closing the main contact. As a result, a rotational force of a motor is delivered from the pinion gear to the ring gear, thereby starting up the engine.
Meanwhile, a starter for an automotive vehicle is usually installed in a space of an area closely spaced from a side of the engine. In many cases, the engine has functional component parts like an air intake pipe with an increasing priority for engine performance. Therefore, it is likely that the starter, having only a startup function, is required to be as small as possible. In order to ensure a market competitiveness of a product per se, it is of increasing importance for the starter to be small in size with a resultant increase in installation capability.
Meanwhile, with a view to improving fuel consumption caused by an important issue of global warming, it is predicted that an idling stop function is widely used in a future. If the idling stop function is employed, the engine is started up with an increased startup frequency, a need arises for the starter to have increased durability. More particularly, main concerns include life of brushes used for a starter motor and increases in durability of the pinion gear and the ring gear.
Increasing developments have been made on brushes of the motor with a focus on materials to provide brushes having long life. The pinion gear and the ring gear mesh with each other on the premise that the meshing is established under an unlubricated condition. This results in a need for material improvement to be made. In addition, improvement needs to be made on a way of meshing engagement per se under a lessened effect of material improvement. To improve the way of meshing engagement per se, it is effective for the pinion gear to be pushed in operation and the motor to be turned on at appropriate timing. In this respect, a known technology, disclosed in Patent Publication 1, is considered to provide an effective result.
With the known technology disclosed in Patent Publication 1, however, the electromagnetic switch, operative to open or close the main contact of the motor circuit, and the electromagnetic force means, operative to push the pinion gear toward the engine, are formed in separate bodies and placed in areas around a circumferential periphery of the motor in parallel to each other. Such a structure causes an increase in dimension of the starter in two directions on a radial direction with respect to a center axis of the motor. This results in a remarkable disadvantage with an increased installation space in dimension of the engine. That is, with a commonly used starter having a single electromagnetic switch with respect to a single motor, there is a need to avoid the occurrence of an interference with the other component parts installed on the engine at a circumferential periphery thereof. A solution to this need is to move the electromagnetic switch on the motor along a circumferential direction thereof at an appropriate angle with respect to a center axis of the motor.
With the starter disclosed in Patent Publication 1, however, the motor carries thereon the electromagnetic switch and the electromagnetic force means in areas parallel to each other and, hence, it is considered that it is often difficult to avoid the interference with the other installed component part in the two directions on the radial direction.